Letter to the Editor

Addition of the Local Volume sample of galaxies from the FAST HI survey

¹ Special Astrophysical Observatory of the Russian Academy of Sciences, N.Arkhyz, KChR, 369167 Russia
e-mail: idkarach@gmail.com
² Main Astronomical Observatory, National Academy of Sciences of Ukraine, Kiev, 03143 Ukraine
e-mail: valkarach@gmail.com
³ National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 1000101 PR China
⁴ Guizhou Radio Astronomical observatory, Guizhou University, Guyang, 550000 PR China
e-mail: cpzhang@nao.cas.cn

Received: 20 February 2024
Accepted: 3 April 2024

Abstract

We report the discovery of 20 new dwarf galaxies in the Local Volume identified as optical counterparts to the Five-hundred-meter Aperture Spherical radio Telescope (FAST) All Sky HI Survey (FASHI) sources. The galaxies have a median stellar mass of 7.8 × 10⁶ M_⊙ and a median HI mass of 1.0 × 10⁷ M_⊙. Most of them are field galaxies, while three are probable members of the M 101 and M 106 groups. We also found seven FASHI radio sources to be probable dark HI clouds in nearby groups. Together with four other known HI clouds in the local groups, their mean-square radial velocity difference of 49 km s⁻¹ with respect to the host galaxies yields an average total mass of (2.7 ± 1.0)×10¹¹ M_⊙ for these groups on the projected scale of 90 kpc.